Is it possible to have Windows RT directly save videos/pictures to the SD Card? I have found guides on how have pictures/videos/music on the SD card to be shown in the gallery/music player, but I haven't found how to have the camera app save images and videos directly to the SD card.

I'm not aware of a single RT app that presents a normal 'Save' dialog. I assume due to no overlapping windows or the lack of any real option settings in the apps yet, along with its push to manage all files via apps vs the opposite.